1. Field of the Invention
This invention relates to communication interface devices and methods, for use in network systems, and more particularly, to devices and methods for operating or monitoring a communication object machine or equipment such as a process controller via a communication network by an information terminal or monitoring device such as a personal computer, the communication object machine or equipment having a communication processing function.
2. Description of the Related Art
Along with improvements to the Internet network environment, there has been proposed a system that utilizes a communication infrastructure in the field of automation, such as a process controller or a building management system. According to the known system, facilities are managed using a general-purpose operating system without preparation of any special network environments and without any dedicated wiring facilities. Also, the cost for constructing the system is low.
An interface device is used for conversion of signals such as data, instruction or the like between a serial communication (RS232C) generally used for the communication object machines and a communication protocol (TCP/IP) for the management device or apparatus (e.g., personal computer) having an internet browser. Hereinafter, the meaning of xe2x80x9cdevicexe2x80x9d includes xe2x80x9capparatusxe2x80x9d and the like. Such an interface device includes a dedicated driver for communicating serially with the communication object machine, a WWW server for connecting with the TCP/IP network of the management devices, and a common gateway interface (CGI) accompanying the WWW server. The CGI stores programs for controlling transmission of signals between the dedicated driver and the CGI.
The CGI is an interface that enables the WWW server not only to present or transmit a file such as an HTML document in response to a demand from the internet browser of the management device, but also to start a particular program in response to the demand from the browser and to present the results to the browser.
In the conventional interface device, however, it is necessary to provide a dedicated driver for effecting the serial communication with the communication object machine, as mentioned above. In addition, it is necessary to prepare a communication procedure or a communication program for activating the program on the WWW server in response to an input from the driver for each of the object machines and to incorporate the communication procedure or program into the driver and the CGI. Therefore, the interface device is required to have a special CPU or a memory having large capacity, resulting in high cost. Also, the program prepared for each machine cannot be used for general purposes.
It is an object of the invention to provide a communication interface device having a simple arrangement that is useful as an interface between a communication object machine such as a process controller and an internet, in which a signal from the communication object machine is directly treated on the internet web (WWW).
It is another object of the invention to provide a general-purpose communication interface device that does not require preparation of a communication program for each of the object machines.
It is another object of the invention to store various different communication programs in each of the object machines in the interface device connected with the object machine or in the object machine itself, thereby making a communication procedure to be an object and removing the necessity of holding the various communication programs in the management device.
It is another object of this invention to provide a communication method for realizing an interface facility between a communication object machine and an internet by a simple structure, and for making the interface useful for general purposes.
The foregoing and other objects are achieved by the following invention.
The invention provides a communication interface device for connecting a communication object machine with a communication network existing between the communication object machine and a management device for operating the machine or monitoring action of the machine, which includes a socket server for converting signals between the machine and the communication network, a WWW server to be connected to the communication network, and a memory connected to the WWW server. The memory stores an application program to be transferred to the management device via the communication network according to a client program prepared in the management device and to be executed on the client program.
The client program used for the invention is typically an internet browser, but is not limited to this. It can be used with other software such as an HTTP client program to acquire HTML files from a WWW server.
The application program can be a general-purpose program, for example, xe2x80x9cJAVA appletxe2x80x9d, xe2x80x9cJAVA Beansxe2x80x9d, xe2x80x9cActive Xxe2x80x9d (a trademark) and so on. The xe2x80x9cJAVA appletxe2x80x9d is a program (application module) described with the JAVA language and can be carried on a browser (HTML). The xe2x80x9cJAVA Beansxe2x80x9d is a part (component module)of the JAVA application described with JAVA. Both of them can be served from a server via the network. The xe2x80x9cActive Xxe2x80x9d is not JAVA, but a component module which can be served via the network.
In this invention, while the socket server converts the signals between the communication object machine and the communication network, the memory connected to the WWW server stores the application program that is delivered according to the client program of the management device and executed on the client program. Therefore, when the WWW server is accessed by the client program of the management device, the information demanded is supplied to the management device from the WWW server via the communication network, and also the application program is executed on the client program of the management device. That is, the application program is incorporated into the client program via the WWW server and is executed. Consequently, a communication between the object-machine and the management device is performed via the socket server.
According to this invention, since the application program is executed on the client program such as internet browsers of the management device side and a communication between the communication object machine and the management device is performed via the socket server, a dedicated driver or program required for the conventional communication interface devices becomes unnecessary, so that the interface device can be constructed simply and at low cost.
Further, since the, operating condition of the application program depends on the performance of the management device, the relative diminution of functionality is avoided such that processing speed of the interface device decreases relatively accompanied with increment in processing speed of the peripheral equipment in a process or the like.
In addition, the interface device can function with various kinds of object machines by merely changing or replacing the application program corresponding to the object machine. Consequently, the interface device has broader applicability than conventional interface devices.
In an embodiment of the communication interface device of this invention, the application program and the HTML document, or other information, can be stored in the memory.
In another embodiment, the application program is a general-purpose program such as xe2x80x9cJAVA appletxe2x80x9d or the like that functions on the internet web (WWW). The management device accesses the interface device to select the application program and execute same on the client program of the management device. Then, the control or monitor of the object machine can be processed by establishing the connection between the management device and the object machine. In this way, since a signal for the communication object machine can be treated directly through the internet by utilizing a program workable on the internet web, the arrangement of the interface device for connection between the internet and the object machine can be compact.
When the JAVA applet is used, the user can be specified and his or her identity can be maintained in secrecy due to the security capability of the JAVA applet. It is suitable for management of the object machines.
In another embodiment, the signal conversion includes a mutual conversion of a communication protocol effective between the communication object machine and the communication network and a communication protocol effective between the socket server and the communication network.
The present invention also provides a communication object machine that functions to communicate with a management device via a communication network, which includes a socket server for converting signals between the communication object machine and the communication network, a WWW server to be connected to the communication network, and a memory connected to the WWW server communication object machine. The memory stores an application program to be transferred to the management device via the communication network according to a client program prepared in the management device and to be executed on the client program.
According to the communication object machine of the invention, it is not necessary to provide a unit for interface, and the communication object machine itself can establish a connection with the management device and execute handling such as setting parameter or monitoring the object machine from the management device.
The present invention also provides a communication method for communicating between a communication object machine and a management device via a communication network existing between the machine and the management device which operates the machine or monitors actions of the machine, which includes the steps of:
connecting the management device to a WWW server according to a client program such as an internet browser stored in the management device;
getting an application program workable on the client program via the communication network from the WWW server;
establishing the connection of the management device to the machine by executing the application program on the management device; and
communicating between the management device and the machine according to the application program.